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Coming up in Silicon Chip Altronics Megabox V2 This new version of Altronics’ Arduino Megabox uses an Arduino Uno or Mega and now has room for two shields and provides an LCD screen, five relays, eight opto-isolated inputs and much more. It will turn your rat’s-nest Arduino prototype into a slick, professional-looking device. Advertising Index Altronics...............................77-84 Ampec Technologies................. 25 Dave Thompson...................... 111 The House of Electrical Horrors Digi-Key Electronics.................... 5 Beware! There are lots of really unsafe electrical appliances available, especially from overseas vendors on sites like eBay and AliExpress. Dr David Maddison describes many of the worst offenders, with plenty of links to YouTube videos showing just how spectacularly dangerous they can be. Emona..................................... IBC Tuneable HF Preamplifier Many low-cost SDR modules have poor HF (3-30MHz) performance. Their wideopen front ends also make them susceptible to cross-modulation from strong signal sources. This simple tuneable preamp greatly improves SDR HF performance. It has adjustable gain control and can run off a 5V supply or phantom power. Hare & Forbes..........................2-3 Jaycar............................ IFC,53-60 Keith Rippon Kit Assembly...... 111 Keysight Technologies........... OBC LD Electronics......................... 111 Universal 6-24V Battery Charge Controller LEACH PCB Assembly............. 11 This Battery Charge Controller turns a ‘dumb’ battery charger into a smart charger, suitable for use with various 6V, 12V or 24V batteries, including leadacid, gel-cell, Li-ion and LiFePO4 (lithium-ion phosphate). It has three preset charging profiles and three adjustable profiles with one to three-stage charging. LEDsales................................. 111 Note: these features are planned or are in preparation and should appear within the next few issues of Silicon Chip. The December 2019 issue is due on sale in newsagents by Thursday, November 28th. Expect postal delivery of subscription copies in Australia between November 25th and December 12th. Notes & Errata 45V 8A Bench Supply, October 2019: in the circuit diagram (Fig.3) on pages 26 & 27, the 1nF capacitor between pins 1 & 2 of IC1a should be 100nF; D6 is an SB380 type; IC1 should have a 100nF bypass capacitor from its negative supply (pin 4) to ground; the 68W resistor below Q3 is a 1W type; the four 0.1W resistors are 1W, not 5W; the 100µF capacitor at the input of REG1 has a 63V rating; and if electrolytics are used for the two 1µF capacitors, their negative leads go to ground. Vintage Radio (Kriesler 31-2), September 2019: the vibrator circuit (Fig.2) shown on page 115 was incorrectly redrawn. The vibrator reed should be shown not touching either of the two contacts. Lintek PCBs................................ 6 Microchip Technology............. 7,89 Mouser Electronics................. 9,73 Ocean Controls......................... 13 SC Micromite BackPack............ 49 Silicon Chip Christmas Tree..... 51 Silicon Chip Shop............. 95,109 Silicon Chip Subscriptions....... 52 The Loudspeaker Kit.com......... 12 Tronixlabs................................ 111 Vintage Radio Repairs............ 111 Wagner Electronics................... 45 WARNING! SILICON CHIP magazine regularly describes projects which employ a mains power supply or produce high voltage. All such projects should be considered dangerous or even lethal if not used safely. Readers are warned that high voltage wiring should be carried out according to the instructions in the articles. When working on these projects use extreme care to ensure that you do not accidentally come into contact with mains AC voltages or high voltage DC. If you are not confident about working with projects employing mains voltages or other high voltages, you are advised not to attempt work on them. Silicon Chip Publications Pty Ltd disclaims any liability for damages should anyone be killed or injured while working on a project or circuit described in any issue of SILICON CHIP magazine. Devices or circuits described in SILICON CHIP may be covered by patents. SILICON CHIP disclaims any liability for the infringement of such patents by the manufacturing or selling of any such equipment. SILICON CHIP also disclaims any liability for projects which are used in such a way as to infringe relevant government regulations and by-laws. Advertisers are warned that they are responsible for the content of all advertisements and that they must conform to the Competition & Consumer Act 2010 or as subsequently amended and to any governmental regulations which are applicable. 112 Silicon Chip Australia’s electronics magazine siliconchip.com.au